Apoggiatura or Appoggiatura: How To spell?

The word Apoggiatura is misspelled against Appoggiatura, a noun meaning "A passing tone preceding an essential tone, and borrowing the time it occupies from that; a short auxiliary or grace note one degree above or below the principal note unless it be of the same harmony; -- generally indicated by a note of smaller size, as in the illustration above. It forms no essential part of the harmony."